Lumber Drying – Stress Free, Stable Lumber

Brooke: Well George, as usual there’s a breeze in west Texas.

George: Brook, you’ve hit on the main reason why we dry lumber this way in Lubbock. We use our west Texas climate for extensive air drying, to dry lumber the natural way.

We bring lumber in on rail cars, green or wet, and after we receive it, we separate it with these sticks to allow the natural airflow to slowly dry our lumber.

Brooke: How long does it take?

George: It takes approximately 6-8 weeks.

Brooke: How do you know when it’s done?

George: We use a moisture monitor and we shoot for 20% or less before we move the lumber into our forced air drying. In the summer, sometimes we can actually get into the low teens, and that allows us to shorten our kiln drying process.

Brooke: So the wood is brought inside next and stacked in these cubicles?

George: Yes after our natural air-drying process, we use a forced-air drying process. It still uses outside air, and it allows a perfect staging area for the next process which is kiln drying.

Brooke: How long does the lumber stay here?

George: One to three weeks.

Brooke: These must be your kilns. Do they have boilers for heat?

George: What we’ve done is we’ve developed a very gentle, low-temperature drying system for our lumber here. It’s actually the dehumidification process.

It works much like the central air conditioning unit in your home. Warm, moist air is circulated over the cooling elements of the air conditioning system. The moisture is removed when the temperature is reduced.

Then the compressor in the system reheats the air so the warm, dry air continues to dry the lumber taking the moisture out of it.

Brooke: It sounds like a big convection oven with humidity control added.

George: That’s exactly right. We take the moisture out of the lumber with our dehumidification system, and then we add moisture back in to equalize and level out the moisture content with these airless spray nozzles.

Brooke: How long will the wood stay in here?

George: The process is a 7-day time cycle; however, in the summer when we bring material off the stack yard, which is already in the lower teens for moisture content, sometimes we can reduce the cycle down to 3 days.

Brooke: I’ve heard other millwork companies talk about 6-8% moisture content as their target. What about you?

George: Well 8-9% is best for our species, outside that range we have difficulties in milling.

Brooke: George, you say your dry quality is better than the lumber mill industry. How do you know?

George: Each month we bring in a NHLA grader in to give us a report card on our drying quality. The industry average for our species is 10-13%, and we’re currently under 3%.

Brooke: So you end up with a superior quality of dry lumber.

George: It’s an excellent foundation for building a shutter.

Brooke: Let’s go on to the next step of how you’re building quality shutters, the Cut Line.